[testing] How to create large PDF files (10MB, 50MB, 100MB, 200MB, 500MB, 1GB, etc.) for testing purposes?

I had problems using pdftk with the cat parameter had a better success with output.

The following command worked for me:

pdftk file_1.pdf file_1.pdf file_1.pdf file_1.pdf cat output.pdf

Using cat produced the following error:

Error: Unexpected text in page range end, here: 
    output.pdf
    Exiting.
    Acceptable keywords, for example: "even" or "odd".
    To rotate pages, use: "north" "south" "east"
        "west" "left" "right" or "down"
Errors encountered.  No output created.
Done.  Input errors, so no output created.

http://www.pdflabs.com/docs/pdftk-cli-examples/.

I created a 172mb PDF is no time at all.